FastLED not working Correctly on Arduino Due

Projects Programming
2 
  for (int i = 0; i < NUM_LEDS; i++) {
    leds[i + 1] = CRGB(255, 0, 0);
    leds[i + 2] = CRGB(255, 0, 0);
    leds[i + 3] = CRGB(255, 0, 0);
    leds[i + 4] = CRGB(0, 0, 0);
    leds[i + 5] = CRGB(0, 0, 0);

    leds[i + 6] = CRGB(255, 140, 80);
    leds[i + 7] = CRGB(255, 140, 80);
    leds[i + 8] = CRGB(255, 140, 80);
    leds[i + 9] = CRGB(255, 140, 80);
    leds[i + 10] = CRGB(255, 140, 80);
  }

What do you reckon is happening here when i approaches NUM_LEDS?

leds(NUM_LEDS, NUM_LEDS + 1);

What is the point of this?